Development of an Acoustic Broken Rail Detection System. High Speed Rail IDEA Program;Final rept. Jul 03-Aug 04

摘要

This project investigated the use of ultrasonic acoustic propagation for detecting broken rail over long distances. The proposed system would use multiple wayside nodes spaced a mile apart to transmit and receive acoustic signals. The lack of a return signal implies the rail has broken. The system would use acoustic propagation in the rail as a digital communication network, allowing the system to provide broken rail protection without the installation of an additional wayside communication system. After a break has occurred the nearest nodes would use echo location to compute a range to the break. Acoustic interactions with rail were studied with frequencies from 3 kHz up to 80 kHz. Longitudinal waves in a few frequency bands were identified as having the lowest attenuation. The construction of a longitudinal wave transducer was attempted but was unsuccessful. Testing demonstrated that operation in the presence of 70 mph trains is possible except when the train is directly over the receiver. A prototype two-node system demonstrating the basic functionality of the system was constructed and operated at a range of 1.3 miles. Algorithms were developed and tested that allowed the prototype to find and track the optimal frequencies and send text data without communication other than through the rail.